Large rolls of sheet material are available for use in photography, product displays, and wherever a temporary backdrop, usually plain but sometimes decorated, is needed. In photographic procedures, rolls of background paper are commonly suspended by inserting a rod through the roll and then attaching the ends of the rod to a pair of lightstands or to a pair of wall or ceiling brackets. Such an arrangement is depicted in FIG. 1 where it will be seen that a roll 10 of sheet material has a rod 11 extending through it. The ends of the rod are supported by brackets 12 carried by a pair of lightstands 13 that in turn rest upon a floor or other support surface.
Such arrangement, although simple, has major shortcomings. Portability is adversely affected by the need to provide two separate lightstands as well as a rod 11 which must be of a length exceeding that of roll 10. While a "short" roll typically is 53 inches in length, if such equipment is to have the capability of supporting rolls of greater length, then the rod must obviously have a length exceeding that of the longest roll to be supported. Such problems might be reduced by forming the rod in sections that can then be joined together to form whatever length is needed, but the requirement for such a rod, even if segmented, nevertheless increases the number and bulk of equipment items that must be transported to and from, or made available at, a work site.
One aspect of this invention lies in providing a highly-effective suspension system that eliminates the need for a support rod and at least one of the lightstands and, therefore, greatly increases the portability of such a support system. A sling suspension is utilized, the system including a pair of hooks adapted to engage the ends of a roll of sheet material and a cable joined to the hooks for central attachment to a single lightstand or other suitable supporting means. Although only a single suspension point is utilized, there is no danger that the suspension cable might engage the ends of a roll to damage those ends, or the side edges of the sheet material of the roll, and interfere with unrolling (and re-rolling, where desired) of the sheet material. The avoidance of such problems results from the distinctive configuration of the hooks and their relationship to other elements of the combination.
Each hook of the pair is generally C-shaped in configuration having an upper shank portion, a base portion, and a lower insert portion. The hooks may be formed of cylindrical bar stock so that the surfaces of the respective portions are rounded and smooth. Of particular importance is the fact that the back and insert portions are substantially straight and merge with each at a right-angled corner.
The shank portion of each hook is connected to one end of the cable at an attachment point. The cable length is selected, based on the length of a roll to be supported by the assembly, so that the attachment point of the cable to each hook is disposed in linear alignment with both the right-angled corner of the hook and the central suspension point from which the cable, and hence the entire assembly, is supported. The result is a system in which the hooks are self-adjusting when their insert portions are received in the open ends of a roll. More particularly, the straight insert portions of the respective hooks become horizontally aligned with each other and the straight back portions of the hooks assume vertical positions against the vertical end faces of the horizontally-extending roll.
Stated differently, when the cable is supported at its mid-point and the insert portions of the hooks are placed within the open ends of a roll of sheet material, the cable and the roll assume the outline of an isosceles triangle. Each equal side of the triangle is defined by the cable and by a projection line coaxial therewith extending through the attachment point (between the end of the cable and the hook) to the right-angled corner of the hook. As a result, the hooks convert the angular suspension forces of the cable into a vertical force vector which is applied upwardly against the engaged undersurface (or inner surface) of the roll and a horizontal force vector which is applied inwardly against the end surfaces of the roll. The angle formed by the imaginary line of projection and the insert portion of each hook should fall within the range of approximately 10 to 45 degrees, preferably 15 to 30 degrees.
Other features, advantages, and objects will appear from the specification and drawings.